How to Use the HAM Antenna Length Calculator
Antenna length determines the resonant frequency in amateur radio. For a half-wave dipole, dividing 468 by the frequency in MHz gives the total length in feet — split that in half for each element's length. For a quarter-wave vertical, dividing 234 by the frequency gives the total length, with ground radials acting as the antenna's other half. Both formulas are standard practical values that account for the end effect of real conductors. Just enter your operating frequency to see the exact length in feet and meters.
Dipole Length by Common Band
| Band | Frequency | Dipole Total Length |
|---|---|---|
| 40m | 7.15MHz | ≈65.5ft (19.95m) |
| 20m | 14.2MHz | ≈33ft (10.04m) |
| 2m | 146MHz | ≈3.2ft (0.98m) |
Frequently Asked Questions
This is the standard practical formula that accounts for the end effect of real conductors, giving a close approximation of a half-wave dipole's total length.
A quarter-wave vertical uses the ground plane as the other half of the antenna, so it only needs half the length of a dipole for the same resonant frequency — but it requires ground radials.